Abstract : The present studies examined the hypothesis that participants who are required to scan for targets would perform better for a number of measures when wearing the monocular night vision goggle than when wearing biocular or the binocular goggles. These findings would be different from the findings discussed in the 1995 report in which participants were not required to scan for targets. No-moon and 3/4 moon experiments were conducted using National Guardsmen. The difficulties that each participant encountered while walking through rough, off-road terrain were recorded by an independent observer. The observer recorded the participant's course-traversal times and the number and types of targets detected. The studies also collected data about subjective preference for the three types of goggles. Results replicated the previous studies, which found that the binocular goggle yielded better performance and was preferred to the other two goggles. The monocular goggle, again, showed no consistent difference from the biocular goggle for any of the four sets of dependent measures. The addition of the target-detection task failed to change the relative ordering of the monocular goggle versus the biocular or binocular goggles.